Pneumatically-operated toggle yard switch

ABSTRACT

A simple, direct, lost-motion linkage connection is provided between the switch operating crank of a conventional toggle-type yard switch and a double-acting pneumatic cylinder whereby the switch can be thrown manually or by a trailing wheel flange, in the customary manner, and, also, automatically by means of a pneumatic cylinder. The lost-motion connection permits operation of the switch in the usual manner through the switch stand or by means of the pneumatic cylinder without either affecting or interfering with the other.

Write ttes tee Speight Jan. 2, 1973 PNEUMATICALLY-OPERATED TOGGLE YARD SWITCH Wesley Y. Speight, Bellaire, Tex.

Assignee: Southern Pacific Transportation Company, Houston, Tex. Filed: Aug. 26, 1970 Appl. No.: 45,265

Inventor:

US. Cl. ..246/393, 246/242, 246/258, 246/41 1 Int. Cl. ..B6ll 5/06 Field of Search ..246/242, 257, 393, 411, 258, 246/284 References Cited UNITED STATES PATENTS 3/1964 Wilson et al .1. ..246/257 x 12/1969 Wilson ..246/242 x 1/1962 9 Bush ..246/258 3,621,237 11/1971 Hylen ..246/411 Primary Examiner-Gerald M. Forlenza Assistant Examiner-George H. Libman Attorney-Bertram H. Mann, Frank B. Pugsley, James G. Ulmer and Delmar L. Sroufe [5 7 ABSTRACT A simple, direct, lost-motion linkage connection is provided between the switch operating crank of a conventional toggle-type yard switch and a double-acting pneumatic cylinder whereby the switch can be thrown manually or by a trailing wheel flange, in the customa- I ry manner, and, also, automatically by means of a pneumatic cylinder. The lost-motion connection permits operation of the switch in the usual manner through the switch stand or by meansof the pneumatic cylinder without either affecting or interfering with the other.

1 Claim, 6 Drawing Figures PATENTEDJM 2 ma SHEET 1 0F 2 INVENTOR WESLEY Y S a/ear A T TORNE Y PA TENTEDM ems SHEET 2 UP 2 WESLEY Y S a/@147 INVENTOR.

A TTOE/VEY PNEUMATICALLY-OPERATED TOGGLE YARD SWITCH BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to railway switches and consists particularly in novel means for providing a pneumatic or other differential fluid pressure control for a manual switch which will not interfere with the manual or trailing wheel actuation of the switch by means of the switch stand.

2. Description of the Prior Art A conventional type of switch stand as used in railway yards is the so-called Pettibone, Mulliken automatic safety switch stand which is disclosed in expired U.S. Pat. No. 1,373,031 of Strom and Erikson. This type of switch stand has a weighted manual lever mounted on a horizontal pivot shaft which acts through a spring toggle and yoke mechanism to throw the switchpoints when the lever is rotated 180. When the wheel of an engine or car passes reversely through the switch, the wheelflange shifts the switch points sufficiently to cause the toggle mechanism to pass over center against its spring bias whereupon the spring bias reverses the toggle and completes the switch movement. Various means have been suggested for providing joint manual and fluid motor controls for switches,

but these have embodied complicated special linkages or directional valve controls.

SUMMARY OF THE INVENTION In accordance with the present invention, a double acting air cylinder or other motor is connected by means of a relatively simple lost-motion linkage, including a unique differential jaw assembly, to the unused arm of the switch point operating crank of a spring-toggle type of switch stand as described above. The lost-motion linkage permits full throwing of the switch points by the motor without movement of the manual lever or otherwise adversely affecting the switch stand. Also, normal actuation of the switch points by means of the stand or a trailing wheel is not adversely affected.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings which illustrate the invention,

FIG. 1 is a plan view of switch operating apparatus embodying the invention.

FIG. 2A is a detailed elevation taken substantially on line 2-2 of FIG. 1.

FIG. 2B is a plan view of the parts in FIG. 2A, but showing the lost-motion linkage connection expanded.

FIG. 3 is a section taken substantially on line 33 of FIG. 2A.

FIG. 4 is a schematic sectional representation of the double acting pneumatic motor and its control valving.

FIG. 5 is a simplified wiring diagram illustrating the purpose and functioning of various parts in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates a stock rail 8 mounted on a pair of ties 9 and 10 and with which is associated a switch point 11 which slides on tie plates 12 and 13 when the switch is thrown and is rigidly secured to an opposite switch point (not shown) by means of a tie bar 14. The switch points are connected to the switch stand by means of an extension 15 of bar 14 extending outwardly beneath rail 8, a pin 16, an adjusting jaw 17, and a switch throw rod 18. The left end of rod 18 is secured to one arm 19 of a double-arm crank mounted beneath base plate 20 of a conventional Pettibone, Mulliken hub safety automatic switch stand in housing 21. The switch stand is mounted by means of flange plates 22 and 23 upon extensions of ties 9 and 10 outwardly of the rails. The base plate 20, housing 21, and flanges 22 and 23, conventionally, are cast integral.

This type of switch stand has a horizontal actuating shaft 24 to which is rotationally rigidly secured an actuating lever 25 weighted at its outer end, as at 26, and normally resting in one of the switch seat clevices 27 or 28. A vertical spindle 29 extends through the housing in line with shaft 24 and at its lower extremity is centrally secured to crank 19, 30. As explained in the above-mentioned Strom et al. US. Pat. No. 1,373,031 and not herein shown, shaft 24 is connected to and actuates spindle 29 through a spring-toggle and yoke arrangement which permits throwing of the switch points manually by means of 180 rotation of lever 25, and automatically by the flange of a trailing wheel moving reversely between rail 8 and switch point 11. The movement of the switch point and connections by the wheel flange serves to shift the toggle over center whereupon the spring bias of the toggle continues the 90 movement of crank 19, 30 to complete the switch throwing action. Normally, arm 30 of the crank, opposite arm 19, connected to switch throw rod 18, is unused, being provided as a reversibility feature. In order to provide for remote control of the switch points, a suitable motor of an 8-inch bore and 4-inch stroke double-acting air cylinder 34, as shown, is mounted on a base plate spanning and supported upon ties 9 and 10 and secured thereto as by lag screws 36, other securing lag screws being shown at 37 extending through flange plates 22 and 23 and securing the same to base plate 35 and the mentioned ties. A fourway valve, generally designated 38, is mounted on the base plate near one edge thereof and is connected to a pressured air supply hose 39 and service hoses 40 and 41 leading to the opposite ends of pneumatic cylinder 34. Valve exhaust nipples 42 and 43 are provided with suitable check valves 44 and 45 and screened outlet nozzles 46 and 47. At the ends of the four-way valve are actuating solenoids 48 and 49 to which are connected wiring conduits 50 and 51 leading from a conduit junction box 52.

Junction box 52 is connected to supply wiring through a conduit 53 and also, by means of wiring in the conduits 54 and 55, to a limit switch 56 and a second conduit junction box 57. The latter junction box is connected by means of wiring in conduit 58 to a second limit switch 59 and by means of wiring in conduits 60 and 61 to a vane-type switch circuit controller 62 which is connected by a controller rod 63 and a lug 64 to switch point 11. Limit switches 56 and 59 also may be of a commercially obtainable magnetic type and are actuated, respectively, by a magnet mounted in a holder 66 which is clamped as at 67 to manual switchoperating lever 25 in such position as to cause closing of switch 56 or 59 as the lever engages either of its clevis seats 28 or 27.

FIG. 4 shows schematically the four-way valve 38 including a slider 70 reciprocable in a casing 71 with the interior of which the fluid pipes or hoses 39, 40, and 41 and exhaust nipples 42 and 43 communicate and at the ends of which are mounted solenoids 48 and 49 connected to the slider for actuation thereof in opposite directions-Energizing wires 50a and 51a are connected to the solenoids. The slider 70 is normally centered, when neither of the solenoids is energized, by means of opposed coil compression springs 73 and 74. Reciprocably received in pneumatic cylinder 34 is a motoring piston 76 to which is centrally secured a piston rod 77 which extends through a packing 78 in the end wall of the cylinder.

FIG. shows in simplified form a wiring diagram incorporating the various electrical components mentioned. At 80 and 81 are shown control switches, manual or otherwise actuated, for remotely throwing the switch points. One solenoid 49 is connected by wiring 51a to power line 83 and control switch 80, thence by wiring 58a to limit switches 59, 56 connected in parallel, thence by a wire 61a to switch circuit controller 62, the movable contact 620 of which is actuated by control rod 63. Circuit controller 62 is also connected as shown by a wire 68 to limit switches 56, 59, thence by wire 54a to main control switch 81 and wires 50a to the other solenoid 48 and power line 83. The movable contact 62a of switch 62 is connected to the other power line 82.

Pneumatic piston rod 77 is connected to the normally unused crank arm 30 of the switch stand by means of a novel lost-motion linkage generally designated 85 and best illustrated in FIGS. 2A and 2B. At the left end of the linkage there is provided a link 86 having an apertured extremity 87 pivoted by means ofa pin 88 integral with the extremity of crank arm 30 (FIG. 1). The right end of link 86 is threadedly secured to a slider or differential block 89 having a right-hand face provided with intersecting concavities 90 and 91. A rib or spline 92 extends centrally along the top wall of link 86.

At the other end of the lost-motion connection there is provided a link-forming jaw including upper and lower plates 94 and 95. At the right end of the jaw there is provided a generally cylindrical pivoting block 96 having reduced cylindrical end bosses 97 and 98 which are rotatably received in similarly shaped openings 99 and 100 in jaw plates 94 and 95. The projecting end of piston rod 77 is threaded into block 96 and secured in position by means of set screws 101. Differential block 89 is of a size and shape to slide in the slot or chamber between jaw plates 94 and 95. Spanning the left ends of jaw plates 94 and 95 are upper and lower blocks 102 and 103 which form inward stop shoulders and are concavely recessed in their opposed surfaces to snugly but slidably encompass link member 86 and key 92 (FIG. 3). As will be evident, differential block 89 forms a shouldered head on link 86 which may slide between pivoting cylinder 96 and stop blocks 102 and 103 as the lost-motion linkage is expanded from the contracted position in FIG. 2A to the expanded position in FIG. 2B.

The novel switch control apparatus operates as follows: Upon closing of one of the main control switches, as 80, if either of the limit switches 56 or 59 is closed and controller switch 62 is also closed, indicating that manual lever 25 is seated and the switch point 11 is in one extreme position, the solenoid 49 will be energized so as to shift four-way valve slider to one extreme position, for instance, that in FIG. 4. Pressured operating fluid, for instance, pneumatic air, will be supplied through connection 40 to the right side of motor piston 76 so as to move the piston in the direction for throwing the switch. Since the stroke of piston 76 is only 4 inches, whereas the necessary switch throw is, for example, 5% inches, an additional throwing force must be provided. This additional force is obtained from the spring toggle mechanism in the switch stand, as described above.

Assuming piston 76 was initially at its rightward position in cylinder 34, the positioning of four-way valve slider 70 as just explained will cause leftward movement of piston 76 for its 4-inch stroke. Lost-motion linkage will be correspondingly shifted in a leftward direction, now abutting blocks 96 and 89 moving together to shift link 86 and to rotate crank 19, 30 counterclockwise sufficiently to move the mentioned spring toggle switch stand mechanism over center. Thereupon, the spring toggle mechanism will continue the rotation of crank 19, 30 to its full extent to produce the full throwing of the switch. This overthrow action of the spring toggle will continue the movement of link 86 leftwardly and cause its headblock 89 to slide between jaw plates 94, 95 to the position of FIG. 2B. Preferably, a small clearance 105 will be provided between the left end of block 89 and stop blocks 102 and 103 at this time to insure full throwing of the switch under the spring toggle action. In case it is desired to again reverse the switch points, the other main control switch 81 will be closed and, if either limit switch 56 or 59 is closed and switch controller 62 positioned reversely from FIG. 5, the other solenoid 48 will be energized to again shift four-way valve slider 70. At the end of the reverse action of link 86 and headblock 89, a small clearance 106 will be provided between the righthand face of the headblock and the jaw end block 96 again to permit complete throwing of the switch points by the spring toggle mechanism. The curved faces and 91 at the right-hand headblock 89 are to insure maximum pressure area with rotational stability in positioning of the headblock jaws and piston rod, while spline rib 92 insures the same rotational stability of positioning between the jaw plates and link 86.

During swinging of lever 25 for manual actuation of the switch points, solenoids 48 and 49 will remain deenergized, due to the opening of both limit switches 56 and 59, so that four-way valve slider 70 will be centered which will have the effect of exhausting both ends of the pneumatic cylinder 34. Manual lever 25 can be rotated back and fourth to rotate the entire spring toggle mechanism and crank 19, 30 sufficiently to cause full throwing of the switch. During this action, link 86 and its headblock 89 will pick up the lost motion between jaw plates 94 and and move the pneumatic piston sufficiently within its cylinder to complete the switch throwing action.

Accordingly, there is provided a relatively simple and effective way of converting a conventional Pettibone, Mulliken type of automatic yard switch into a remotely controlled switch utilizing a pneumatic motor for the purpose. Of course, other types of control motors may be used and the powering and control thereof designed appropriately. The invention may be modified in various respects as will occur to those skilled in the art, and the exclusive use of all modifications as come within the scope of the appended claims is contemplated.

Iclaim:

1. For use with a railroad switch stand of the automatic type having a manual switch operating lever, a switch throw rod, and means for connecting said lever to said rod including a spindle extending transversely of said rod, a double arm lever rigid with said spindle and having a first arm connected to said rod, and an over center, spring-biased toggle mechanism connecting said spindle and said manual lever whereby said switch can be thrown independently by swinging of said manual lever and by a trailing wheel passing through the switch,

additional actuating means for the switch including a double-acting motor, a lost-motion connection between said motor and the other arm of said double arm lever and having slidably interfitting lostmotion parts, a control device for said motor having first and second positions, respectively, for causing operation of said motor for throwing said switch in opposite directions and a third, neutral position, means normally biasing said control device to said neutral position, whereby inactivation of said additional activating means will not adversely affect throwing of said switch by said lever or a trailing wheel, switch actuating control means for selectively shifting said control device to said first and second positions, and a common integral mounting plate for the switch stand and said motor whereby both said switch stand and said motor may be adjusted relative to the switch by adjustment of said plate. 

1. For use with a railroad switch stand of the automatic type having a manual switch operating lever, a switch throw rod, and means for connecting said lever to said rod including a spindle extending transversely of said rod, a double arm lever rigid with said spindle and having a first arm connected to said rod, and an over center, spring-biased toggle mechanism connecting said spindle and said manual lever whereby said switch can be thrown independently by swinging of said manual lever and by a trailing wheel passing through the switch, additional actuating means for the switch including a doubleacting motor, a lost-motion connection between said motor and the other arm of said double arm lever and having slidably interfitting lost-motion parts, a control device for said motor having first and second positions, respectively, for causing operation of said motor for throwing said switch in opposite directions and a third, neutral position, means normally biasing said control device to said neutral position, whereby inactivation of said additional activating means will not adversely affect throwing of said switch by said lever or a trailing wheel, switch actuating control means for selectively shifting said control device to said first and second pOsitions, and a common integral mounting plate for the switch stand and said motor whereby both said switch stand and said motor may be adjusted relative to the switch by adjustment of said plate. 